A mobile ad hoc network, MANET, is a communication network that is formed in a more or less spontaneous way and comprises an arbitrary number of participating nodes. It typically comprises wireless communication terminals forming a wireless stand-alone network that is not dependent upon any external network infrastructure. Major motivations for using ad hoc networks include ease and speed of deployment, and decreased or non-dependence upon any infrastructure.
An important property of ad hoc networks is that terminals are able to communicate with each other directly, either through a direct communication from terminal to terminal, or from one terminal to another using other terminals. Terminals participating in the network relay information destined to other terminals in the network. A terminal is here defined as any device, or part of a device, that is able to communicate with other devices, or parts of devices. In the same way, a mobile terminal is defined as a terminal that is either completely mobile, or part of another device, for example a vehicle, that is mobile.
By the introduction of future networks, using technologies such as Ipv6, a larger address space will be available that, together with other future network features, will make ad hoc networks easier to configure and administrate, and therefore more and more attractive.
There are many situations where an ad hoc network may be useful. People meeting at a conference might want to exchange information such as files or documents, without the need for any cables and cumbersome configurations. Search and rescue operations may involve the need to quickly set up a communication network in situations where none or very little communication infrastructure is available.
There are also more common civilian applications to ad hoc networks. Ad hoc networks and their capabilities have the potential of establishing communication networks between users in ways that are being done today in cellular and/or wireless networks. In some places and situations ad hoc networks may provide the capabilities and possibilities of extending, complementing, or even replacing cellular and wireless networks. If an event occurs that causes a lot of people to gather in a certain area that normally is sparsely populated, or even unpopulated, a cellular or wireless network might not be existent, or have enough resources to handle the increased and spontaneously newly formed demand. An ad hoc network can in a situation like this automatically be formed between every communication device, thus replacing the need for other network infrastructures.
Wireless mesh networks resemble ad hoc networks and have the same network properties, except that nodes are not moving. Mesh networks can therefore be regarded as static ad hoc networks. In this way mesh networks can be a more permanent form of ad hoc networks, which may be operated by a more permanent source of power, although this is not necessary.
Mesh networks can also be used as a wireless infrastructure, a wireless network where the infrastructure itself is wirelessly connected. This differs from how present cellular and wireless networks normally are organized, where access to the network within a cell or area is wireless, but where each cell is connected in a wired infrastructure.
One example of this is WiMax mesh networks, constructed with WiMax technology, which resemble static ad hoc networks and mesh network with a wireless infrastructure, with the addition of the static areas where mobility is possible. Access to such a network, or any other type described here, can for example be made with or without the aid of an ad hoc network.
Another example are the so called VANETs (Vehicular Ad hoc NETworks) where the mobile nodes may be different vehicles, such as cars, trucks, trains etc, that are interconnected by mobile networks of ad hoc type. These networks are characterized by the primary nodes, i.e. the cars, trucks etc, having a more permanent source of power and often better antenna capacity. Mobile nodes and user terminals such as mobile phones, PDAs, or other information equipments within the network, can then get access to different forms of information and communication services.
Other types of networks will gradually be developed in the years ahead, but the principle will be the same, the coordination of different types of networks in order to maximize the geographical coverage area and at the same time minimize costs of enlargement and maintenance, with constraints on acceptable or demanded quality of service and performance.
The innovation described below can with advantage be used in all these, both present and future, communication networks.
If we consider a situation in a normal urban area where we have a large number of users, we might consider another application of ad hoc networks, i.e. Metropolitan Area ad hoc Network, (MAN). If a sufficient number of users are willing to use their own devices and resources to participate in an ad hoc network, we may envision a scenario where communications such as voice calls, or some other form of data traffic, are taking place within the ad hoc network itself, instead of in the cellular or wireless network, if such a network exists. In situations like these, we should consider one important difference between these two types of networks. In a cellular or wireless network, an operator is responsible for providing and maintaining the infrastructure that enables the communications. However, building and maintaining a cellular and/or wireless network is an expensive business that is financed by users subscribing to the cellular or wireless services and paying a fee. If we on the other hand consider an ad hoc network formed in a spontaneous way by the users and their devices, the “infrastructure” of the ad hoc network is owned, or maintained by the users themselves. It is therefore natural to assume that since users are using their own resources to maintain the network, they may also be allowed to operate within the network without charge. This may be considered as a situation involving a conflict of interest, regarding charging of communication, between network operators and providers on the one hand and individual users on the other hand. This problem is addressed by the present invention as will be discussed in the following.
Examples of charging procedures in ad hoc networks include published US patent application 2005/0220101. In US 2005/0220101 is described a method of performing charging and rewarding processes in ad hoc networks. Here, a network infrastructure plays a vital role in the handling of charging information, making charging difficult in stand-alone networks.